Present radar for Ballistic Missile Defense signal processing and data representation is capable of producing a picture of debris (small fragments of irregular shape and mass) as a dense field of closely spaced objects. However it is difficult to separate the lethal object (e.g. a ballistic missile) from the field of debris. Debris encompasses certain types of objects in a ballistic missile threat complex, whether intentional or unintentional in origin, that complicate discrimination of the lethal object by presenting a field of closely-spaced fragments that are physically small and non-symmetric in shape and radar pattern, and execute non-simple rotational motion. Examples of debris are the fragments of spent fuel released during solid rocket termination, and the bi-products of intentional fragmentation (explosion) of a final stage booster tank.
A number of methods have been used to remove debris indications. A common method is to form a track on the debris as well as on the objects of interest. Then discrimination of the debris from the lethal object is performed by identifying the object(s) of interest based on long-term behavioral characteristics, such as by using a Bayes network. This method uses an enormous amount of radar resources to track the debris and the object(s) of interest. Another method used is to filter the debris and the object based on their radar cross-section (RCS). However, in challenging cases, the RCS of the threatening object may be smaller than many or most of the detected debris fragments, rendering bulk filtering based on RCS ineffective.
Also, because existing techniques may require tracking of the debris or otherwise require long processing times to discriminate the debris from the object(s) of interest, the distribution of deployment velocities for the debris fragments may be such that they continue to complicate the radar scene throughout the exoatmospheric phase of flight, before finally being stripped away during the endoatmospheric re-entry phase. Accordingly, it is desirable to screen out early in the engagement a potentially large numbers of debris objects, with few missed detections of the lethal object (low leakage), in order to concentrate focus of attention and expend radar resources on potentially threatening principal objects. The need to accomplish this screening is particularly critical in the case of a future tactical sea-based radar operating against short- and medium-range ballistic missile threats in the naval theatre. If debris generated in the exoatmosphere is not handled early, the terminal re-entry phase becomes the one opportunity to perform discrimination, and this may be too late.
Thus, a rapid and accurate method and system to distinguish debris from objects of interest is needed.